


The Structural Integrity of Complex Polyhedra

by BrighteyedJill



Category: Sherlock (TV)
Genre: Dom/sub, Kink Negotiation, M/M, Multi, Polyamory, Power Dynamics
Language: English
Status: Completed
Published: 2012-01-05
Updated: 2012-01-05
Packaged: 2017-11-06 13:31:26
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,821
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/419450
Author URL: https://archiveofourown.org/users/BrighteyedJill/pseuds/BrighteyedJill
Summary: <blockquote class="userstuff">
              <p>Sherlock doesn’t understand John’s reaction to this case, so he goes to Lestrade for assistance.</p>
            </blockquote>





	The Structural Integrity of Complex Polyhedra

**Author's Note:**

> Written for [](http://noirrosaleen.livejournal.com/profile)[**noirrosaleen**](http://noirrosaleen.livejournal.com/) as a gift for [](http://sherlockmas.livejournal.com/profile)[**sherlockmas**](http://sherlockmas.livejournal.com/). Thanks to [](http://jaune-chat.livejournal.com/profile)[**jaune_chat**](http://jaune-chat.livejournal.com/) for beta-ing.  
> 

When the sitting room door closed behind them, Sherlock caught John’s hand and dropped to his knees. He pressed his forehead to the back of John’s hand. “I’m sorry, John.”

John’s eyes remained focused on the far wall. His unfettered hand, the right one, smoothed down his shirt and caught against the dried blood on the front. He wiped his hand on his trousers. “I can’t do this now.” His voice barely rose above the hiss of the radiators, the rumble of the traffic on the street, and the heartbeat that throbbed relentlessly within Sherlock.

John tugged his hand free and settled it briefly against the line of Sherlock’s jaw. He looked at Sherlock, at last, at last. “Get cleaned up and go to bed.”

Sherlock listened as John trudged across the flat. His steps were heavier than usual, and fractionally uneven: a hint of the limp had returned. John’s steps faded up the stairs and did not return again.

Sherlock stayed for a long time, until his knees began to ache, and he could hold that pain as a shield against his growing dread.  
\--

The next morning, Sherlock went to New Scotland Yard. He timed his arrival to coincide with Lestrade’s, and caught up with him in the foyer.

“I require your assistance,” he announced.

“What’s happened? Is it about that tosser from last night?”

“No, no. Not the case. It’s more important than that.” Sherlock realized his voice had got rather louder than usual, and he clenched his jaw to prevent himself from saying anything else.

Lestrade’s brow furrowed as he ran his eyes over Sherlock, looking for clues in his own, pedestrian way. Sherlock could have told him that the heart of his problem lay far below the surface. A burst of laughter intruded from the other side of the doors, making them both tense. Lestrade grabbed Sherlock’s arm and tugged him aside, into the stairwell, away from prying eyes. He kept his grip on Sherlock. “You’re shaking.”

“As ever, your powers of observation are astounding.” Sherlock tried to make his tone even, but he recognized that his words lacked their usual bite.

“Alright.” Lestrade squeezed Sherlock’s arm with bruising force that sent a delicious shiver through Sherlock. “What’s this all about?” Sherlock looked intently at the wall without answering. Lestrade was clearly about to press further when his phone chimed--Sherlock recognized the sound as an incoming text message--and his hand fell back to his side. “Go to my office. Draw the blinds. I’ll be there in a moment.”

A wave of calm swelled through Sherlock’s system, leaving him free to walk away under his own power. He strode through New Scotland Yard like the master of the universe, with raised chin and haughty expression, until he reached the safety of Lestrade’s office and could close out the world.

Sherlock’s agile mind raced through calculations on what Lestrade might do to him. They didn’t have nearly the time or freedom for what Sherlock craved right now, but there were other options. Surely Lestrade could give him something to dull the edge of his need so he could bloody concentrate.

When Lestrade arrived, his movements were taut and controlled, with none of the easy promise he’d displayed only moments ago. Sherlock re-assessed the data. “You received a text from John,” he said.

“Yeah.” Lestrade closed the door firmly behind him before turning to deliver a dark look. “And I’ll please you not to pull this ‘ask your father’ bollocks on me.”

Sherlock saw his hope of relief fading as Lestrade’s eyes hardened. “Gregory.” He dropped to his knees without hesitation or finesse, and Lestrade winced. “I wouldn’t have you do anything he’d object to. But I need… I need something. I feel as if I might... If it all might...” He gestured sharply as his words failed him.

“Don’t do that, love.” Lestrade came to Sherlock immediately. He tangled the fingers of both hands into Sherlock’s hair as he lowered himself slowly to one knee. “We won’t let you disappear.”

Sherlock closed his eyes and leaned into Lestrade’s touch, pathetically grateful for the reassurance. For hours, he’d felt that he was teetering on the edge of something disastrous. Lestrade had seen him worse than this: strung out on his need for harder things than his lovers’ touch. Accordingly, the humiliation Sherlock felt at the acuity of his need didn’t cut as keenly as he had last night, under John’s careful non-attention. Sherlock kept his eyes closed. “He wouldn’t even look at me.”

“Do you want to know a secret?” Lestrade asked.

Sherlock cracked an eye open. “Something I don’t already know, you mean?”

“I think he’s frightened.”

“Of me?”

Lestrade huffed out a chuckle. “You may be a formidable man, but you don’t scare John Watson.”

“Then what?” Sherlock’s buzzing mind paged through the previous evening’s events, from the messy conclusion of the case to John’s strategic retreat.

“You can’t work it out?”

“No!” Sherlock’s hands clenched into fists, and he observed, dimly, that he was gripping Lestrade’s shirt. “I’m bloody useless in this state. He knows that. I thought he _understood_ that.”

“Oh, he understands.” Lestrade slid his hands down to rest atop Sherlock’s shoulders. “Tell me something. Did you break any of the rules?”

“No!”

“Are you certain?”

Sherlock forced himself to review the rules, careful to miss nothing in his excited state:

_1\. Sussex means stop.  
2\. Not on a case.  
2a. In fact, not outside of the flat without previous discussion.  
2b. Lestrade’s flat is a standing exception, of course, don’t be a prat.  
3\. Do not lie to John.  
3a. Do not lie to Lestrade (about This or anything related to This).  
3b. Ever._

“I didn’t.” Sherlock’s mind spun through possible reasons for John’s displeasure. His grip on Lestrade tightened. “Gregory, how am I meant to—“

“Hush,” Lestrade commanded. His voice was no louder or lower, but something in it compelled Sherlock to obey.

Lestrade pushed himself to standing and walked behind his desk. He snapped his fingers. “Up.”

Sherlock stood. He felt the calm returning already, as if he’d taken a hit of control, and it was wending through his bloodstream.

“Come stand by the desk, face me. Half a metre away.”

Sherlock obeyed. His eyes measured the distance precisely, and he positioned the toes of his shoes against an invisible line.

“Bend forward and place your hands on the desk, heel of your palm against the edge.”

Sherlock did so. His eyes took in every detail of the papers over which he spread his hands.

“Widen your stance.”

Sherlock moved his left foot, spreading his legs further apart. Even if he still wore all his clothes, even if the position to which Lestrade had directed him was not beyond the bounds of propriety, Sherlock felt obscenely exposed. The calm was spreading within him faster than the effects of cocaine.

“Very nice, Sherlock.” Lestrade sat. “Stay where you are. You can close your eyes, or you can look at me, but nowhere else. I’m going to give you a question to think about, and that’s what I want you to focus your attention on. When we’re finished, I’m going to ask you for an answer. Do you understand?”

Sherlock bit back his, “Of course I understand,” and said, instead, “Yes.”

“Good. I’d like you to consider what it was that frightened John.” Lestrade picked up a pen and began to write.

Sherlock’s eyes lingered on Lestrade’s face before he realized his thoughts were swirling in the wrong direction: what form was Lestrade filling out, where had he stopped for coffee this morning, why had he set Sherlock this particular question? No, Sherlock admonished himself. He’d been ordered to consider John.

Sherlock narrowed his attention to a fine point, which he applied to the previous evening’s events. The victim had been dead when they broke into the flat, and dead bodies as a rule did not bother John. John had got blood on his shirt whilst checking the body for signs of life, but that, too, was not atypical. The pursuit of the blackmailer-turned-murderer had been exhilarating, but not particularly alarming. The man had got a head start down Royal Hospital Road, and Sherlock had caught sight of him clamouring over the wall into the Chelsea Physic Garden.

Sherlock had, of course, pursued. He squeezed his eyes closed, playing the scene over in his mind:

_Sherlock dropped over the wall, scanned the dark garden, and locked his eyes onto the retreating figure of the killer. Behind him, he heard John drop to the ground with a grunt. Sherlock dashed off after his quarry, who had disappeared past a screen of trees. He ran, dodging bushes and benches in the dim light, until he sped around the side of the glasshouse right into the path of a fist that laid him out on his back._

_Before the daze subsided, the attacker had Sherlock restrained, sitting astride his hips and pinning Sherlock’s hands to the cold ground with his knees. A trained grappler. Of course—he must have met the victim’s brother through their trainer._

_The man leaned in close and pressed a knife to Sherlock’s throat, above his scarf. A sticky drop of fluid dripped onto Sherlock’s skin. Blood. He hadn’t had time to clean the blade. “Quiet now, my dear,” the man whispered. “Don’t call your guard dog, or I’ll slit your pretty throat.”_

_Sherlock pushed his head down against the ground, relieving some of the pressure from the blade. He pitched his voice low. “He won’t leave until he’s found us, you realise.”_

_“Quiet, I said.”_

_Sherlock looked closely at the man’s face—what he could see of it in the deepening shadows—and read fear there. “Scotland Yard already knows all about you.”_

_“They couldn’t possibly. Shut up.”_

_“They know you live in Hoxton and frequent The Eagle. You work as a mobile phone salesman, but aspire to earn fame through sport. You’ve been dating Elizabeth Landers for seven months, and you killed her when she confronted you about your scheme to blackmail her brother.”_

_“I said shut it.”_

_“You’d best give yourself up now. The Met will track you down regardless, but causing harm to a detective would hardly ingratiate you to the court.”_

_“If I go, I’m taking you with me.” The man drew back his knife._

_John’s attack didn’t come as a complete surprise, since Sherlock had spotted him watching from the bushes thirty seconds previous. However, seeing John’s boot connect with the man’s jaw at close range was an unexpected treat. The kick sent the man tumbling onto his back. John braced his foot against the man’s shoulder and tensed to continue the fight, but the main remained limp, eyes closed._

_John turned and reached down to Sherlock, who took his hands and allowed himself to be pulled up. John wiped a hand across Sherlock’s neck, smearing the drop of blood._

_“Not mine,” Sherlock muttered._

_John grabbed Sherlock’s shoulders and pushed him against the nearest tree. He crushed his mouth to Sherlock’s, declaring his relief with a vigorous kiss. His hands drifted down to bracelet Sherlock’s wrists, pinning him against the tree. Sherlock’s blood was up from the chase, and this—John restraining him—set his heart pounding even faster. He spread his legs a bit, letting himself be held, helpless, while John reclaimed him._

_John’s thigh pressed between Sherlock’s legs, and arousal burst through Sherlock, drowning out all other data streams. “You’re alright,” John breathed. “And you’re mine.”_

_Sherlock leaned forward to whisper in John’s ear, and that’s when he saw the moving blur of the supposedly downed criminal. He moved, swinging himself and John aside in one movement that carried them out of the path of the criminal’s knife._

_The weapon thunked into the bark of the tree, embedding itself just where Sherlock had been standing._

_Sherlock pulled his hands out of John’s grip, turned, and delivered an open-handed blow to the man’s chin that sent him stumbling backwards, releasing the buried knife. Sherlock followed up with three more precise strikes, and this time the man teetered on his feet before dropping heavily to the ground, unconscious._

_John appeared beside Sherlock, staring down at the well-and-truly incapacitated criminal. His hands clenched into fists. After a moment, he pulled his phone from his pocket and dialled. “Lestrade? You had best come and get your man.”_

_Sherlock rummaged through the criminal’s pockets while he waited for the Met to arrive, but didn’t find out anything he hadn’t already deduced. In truth, his continued investigation served mostly to keep him distracted while the arousal John had kindled simmered inside him._

_Sherlock knew the rules; he’d wait until they’d returned to the flat, but he wouldn’t be able to wait any longer than that. Already the desire to feel John’s hands on him, to yield to John’s command was crowding out thoughts of work. With the case solved, he could allow himself this pleasure. He knew John would be able to control him. He relied upon it._

“Sherlock.”

Sherlock’s eyes snapped open, and he found himself facing Lestrade over the desk. He was in New Scotland Yard, in Lestrade’s office, under Lestrade’s control.

“Do you have an answer?”

Sherlock shook his head.

Lestrade’s eyes narrowed, but after a moment of observation, he nodded. “Alright. In a moment, I’ll let you leave, but you’re not to return to Baker Street until suppertime. And you’re not to seek out John until then, either. We’ll deal with this together. Tonight, yeah?”

Sherlock dropped his gaze to the desk. He hadn’t found the answer he’d sought, but at least Lestrade had outlined a path for them to find it. The wide abyss of uncertainty had been neatly ordered at Lestrade’s command, and now Sherlock could at least bear to wait. “Yes.”

“Good. Stand up. You’re dismissed.” Lestrade rose from his desk and pulled open a file cabinet. He threw a glance over his shoulder, and looked Sherlock up and down. His eyes snagged on the bulge at the front of Sherlock’s trousers. “And button your coat before you go out. I don’t need that lot speculating what we get up to in here.”

“Of course, Detective Inspector.”  
\--

Sherlock stopped at the door to 221 and observed with his whole body. He found no clues to suggest what awaited him inside. His walking around the W1 all afternoon had likewise produced no conclusions. He’d meant to observe the shopping habits of women with young children; he suspected an outing to the shops might figure in to a cold case he’d been picking at in the past weeks. Furthermore, the previous evening’s dusting of snow had increased the attraction of Marylebone High Street, because it allowed him to practice identifying the tracks of various kinds of footwear. He’d succeeded in distracting himself for a few hours, until the calm Lestrade had imparted begun to crumble against repeated encroachments by thoughts of what awaited him at home.

Sherlock had managed to stay away from the flat until what John would call—rather erroneously, in Sherlock’s opinion—“a reasonable man’s supper time.” Now, Sherlock saw no clues that announced for certain whether or not John was inside. Nothing for it but to get more data.

Sherlock slipped inside and eased the door closed. He could hear Mrs. Hudson humming in her kitchen, slightly off-key, but enthusiastic as always. He trod carefully up the stairs, skipping the eleventh step, which had a loud creak. The door to the sitting room stood slightly ajar. Sherlock ghosted over to the door and peeked through.

Lestrade was sitting on the coffee table, leaning in with his hands on John’s knees. John sat with his fingers clenched over the front edge of the sofa, his whole body angled forward, his face inches from Lestrade’s. Sherlock drew away from the door and settled against the wall, listening intently. It took him a moment to tune in to their low conversation.

“…not the worst thing in the world. You’re only human, John.”

“It’s not safe. One of us has to understand the limits of this thing, or…”

“Or what?”

“Don’t be daft. Someone could get hurt.”

“A bit the point, that is.”

“You know what I mean,” John said. “Really hurt.”

“I don’t believe for a second that you’d carry on if ‘Sussex’ came out of his mouth.”

“Of course not.”

“Then what?”

A pause: some sort of gesture from John, most likely.

“You think he’ll not do it?” Lestrade asked. “That he’d let you go beyond what he wanted?”

“Limits aren’t really his area.”

“Nor yours, in truth. That’s the rub, isn’t it? You don’t trust yourself in this. For Christ’s sake, John.” Another pause. Sherlock wished he could see Lestrade’s expression. “This thing we have is not one-sided.”

“I thought it was three-sided.”

“That, too. I mean to say… Look, being dominant is not about knowing everything, about being everything. You need what Sherlock has to offer as badly as he needs what you can give him. Let him help you.”

“It feels a bit like running over the edge of a cliff.”

“Will do. Will sometimes feel like falling, other times like flying.”

“That’s encouraging.”

“I’m full of pep talks. Though ‘chin up you mad bastard’ talks are more my speciality.”

“Is that what this is?”

“My second one of the day. I should charge. Or at least put it on my CV.”

“Ha bloody ha.”

“You are alright, for all that? You look a bit of a mess.”

“Ta ever so.”

“Did you manage to get any work done at all?”

“Sarah sent me home at half ten after I mistakenly told a Welsh pensioner he was pregnant.” Another pause. Sherlock speculated about smiles and raised eyebrows. John said, “I was looking at the wrong chart.”

John’s giggle and Lestrade’s accompanying chuckle mingled and floated out into the hallway.

Sherlock pushed open the door and stepped into the room.

Lestrade looked up with a sly smile. “Oh good. You heard.”

John’s giggle faded into a sorry attempt at a stern frown. “Eavesdropping again, really Sherlock?”

Sherlock unwound his scarf from his neck and flung it over the armchair. His coat followed. The air in the flat was warm, but Sherlock still imagined that he could still feel the heat on the skin of his wrists where John had pinned his hands last night. “I don’t know what you mean,” he said absently.

“Words I seldom hear coming out of that mouth.” Lestrade stood. “Lock the door, Sherlock,” he said, and moved to sit next to John on the couch.

Sherlock debated for a moment whether to kneel, but since that hadn’t worked for him in recent attempts, he decided to sit on the coffee table: a humble enough place with the added advantage of being within touching distance of both Lestrade and John. Once he was settled, he told Lestrade, “I believe I found the answer you set me looking for this morning.”

“Good.” Lestrade nodded. “Knew you’d catch on eventually.”

“John’s afraid one of us will come to harm because of this.” He waved a hand to indicate the three of them. “That our... _dynamic_ will somehow interfere with a case.”

“I made a mistake,” John said. He was looking not at Sherlock, but at Lestrade’s hand twined with his against the sofa cushion. “You could have got hurt.”

“Our work is dangerous, John,” Sherlock said. “Any one of us could get hurt, whether or not we’re kissing on the job.”

“Though technically someone did violate the ‘not outside the flat’ rule,” Lestrade put in.

“See what I mean?” John said. “If I can’t be trusted to follow the rules, how am I--?”

“Sherlock,” Lestrade interrupted. “Would you like to answer this one?”

“It’s very simple, John,” Sherlock said, in the tone he used when explaining obvious deductions that those around him nevertheless seemed to miss. He wanted, very much, for John to understand this point. “I couldn’t do what I do without you and Lestrade. I couldn’t have the space in my mind to think, much less work, if you weren’t... if you didn’t...” He looked back at Lestrade, loathe to ask for help, but also certain he hadn’t quite made his point.

“I think what Sherlock’s trying to say is that some unauthorized snogging now and then is a fair price to pay for having a relationship that works as well as this one does.”

“Does it work?” John looked up from his careful study of nothing to glance between them. “That’s really the question, isn’t it? What you had before I came on the scene... You balanced each other. I thought...” He took a deep breath. “If you want to go back to the way things were, I won’t stand in your way.”

Sherlock’s eyes slid over to Lestrade, and he found an equally stunned glance answering his own. Then a quirk of Lestrade’s eyebrow showed him they had an understanding.

“You’re an idiot,” Sherlock said. His eyes slid back to John.

“I hate to encourage him,” Lestrade said, “but he’s right. You’re an idiot, John Watson.”

Sherlock’s heart, which had seemed to shrink in his chest at John’s misguided declaration, beat strongly again as he realized that he and Lestrade, united, were certain to win the day. Now there was only to fully demonstrate to John how very well their dynamic did, in fact, work. He could already feel himself drifting into the mental state that opened him to all that John and Lestrade could do to him. With that mental drift came the arousal of his body, a stirring in his blood that wouldn’t be denied again, not tonight.

John’s eyes widened as Sherlock slid to the floor between John’s legs. Lestrade smiled and leaned in close to John’s ear. “You’re staying right here, right between us. You’re going to hold still and stay quiet while I direct Sherlock in sucking your cock just the way you like it, and then you’re going to sit there and let him ride you until you both finish.”

“Oh,” John said, in a voice that was mostly breath and very little sound.

Sherlock leaned in between John’s thighs and breathed out slowly, deliberately, against the stretched material of John’s trousers.

John’s grip on the sofa tightened. With apparent effort, he dragged his gaze away from Sherlock and looked at Lestrade. “And what about you?”

Lestrade smiled, confident and easy. “Must I think of everything?”

“No.” John returned his smile. “No.” He glanced down at Sherlock and raised his eyebrows in inquiry.

Sherlock looked between his lovers, and felt his need settle from a painful, insistent throb to a simmering arousal he could endure, secure in the knowledge that all would be taken care of. He said, “I’m certain we can come up with something we’ll like.”


End file.
